/*!
 * \file      modem_utilities.c
 *
 * \brief     utilities for modem
 *
 * Revised BSD License
 * Copyright Semtech Corporation 2020. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the Semtech corporation nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL SEMTECH CORPORATION BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "modem_utilities.h"

static inline unsigned my_bswap32(unsigned x) {
  return ((x << 24) & 0xff000000 ) |
  ((x << 8) & 0x00ff0000 ) |
  ((x >> 8) & 0x0000ff00 ) |
  ((x >> 24) & 0x000000ff );
}

#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
#define ENDIAN_n2b32( x ) my_bswap32( x )
#else
#define ENDIAN_n2b32( x ) ( x )
#endif

// ------------------------------------------------
// SHA-256

#define ROR( a, b ) ( ( ( a ) >> ( b ) ) | ( ( a ) << ( 32 - ( b ) ) ) )

#define CH( x, y, z ) ( ( ( x ) & ( y ) ) ^ ( ~( x ) & ( z ) ) )
#define MAJ( x, y, z ) ( ( ( x ) & ( y ) ) ^ ( ( x ) & ( z ) ) ^ ( ( y ) & ( z ) ) )
#define EP0( x ) ( ROR( x, 2 ) ^ ROR( x, 13 ) ^ ROR( x, 22 ) )
#define EP1( x ) ( ROR( x, 6 ) ^ ROR( x, 11 ) ^ ROR( x, 25 ) )
#define SIG0( x ) ( ROR( x, 7 ) ^ ROR( x, 18 ) ^ ( ( x ) >> 3 ) )
#define SIG1( x ) ( ROR( x, 17 ) ^ ROR( x, 19 ) ^ ( ( x ) >> 10 ) )

static void sha256_do( uint32_t* state, const uint8_t* block )
{
    static const uint32_t K[64] = { 0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4,
                                    0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe,
                                    0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f,
                                    0x4a7484aa, 0x5cb0a9dc, 0x76f988da, 0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
                                    0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc,
                                    0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b,
                                    0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070, 0x19a4c116,
                                    0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
                                    0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7,
                                    0xc67178f2 };

    uint32_t a, b, c, d, e, f, g, h, i, j, t1, t2, w[64];

    for( i = 0, j = 0; i < 16; i++, j += 4 )
    {
        w[i] = ( block[j] << 24 ) | ( block[j + 1] << 16 ) | ( block[j + 2] << 8 ) | ( block[j + 3] );
    }
    for( ; i < 64; i++ )
    {
        w[i] = SIG1( w[i - 2] ) + w[i - 7] + SIG0( w[i - 15] ) + w[i - 16];
    }

    a = state[0];
    b = state[1];
    c = state[2];
    d = state[3];
    e = state[4];
    f = state[5];
    g = state[6];
    h = state[7];

    for( i = 0; i < 64; i++ )
    {
        t1 = h + EP1( e ) + CH( e, f, g ) + K[i] + w[i];
        t2 = EP0( a ) + MAJ( a, b, c );
        h  = g;
        g  = f;
        f  = e;
        e  = d + t1;
        d  = c;
        c  = b;
        b  = a;
        a  = t1 + t2;
    }

    state[0] += a;
    state[1] += b;
    state[2] += c;
    state[3] += d;
    state[4] += e;
    state[5] += f;
    state[6] += g;
    state[7] += h;
}

#undef ROR
#undef CH
#undef MAJ
#undef EP0
#undef EP1
#undef SIG0
#undef SIG1

void sha256( uint32_t* hash, const uint8_t* msg, uint32_t len )
{
    uint32_t state[8] = {
        0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19
    };

    uint32_t bitlen = len << 3;
    while( 1 )
    {
        if( len < 64 )
        {
            union
            {
                uint8_t  bytes[64];
                uint32_t words[16];
            } tmp;
            memset( tmp.words, 0, sizeof( tmp ) );
            memcpy( tmp.bytes, msg, len );
            tmp.bytes[len] = 0x80;
            if( len < 56 )
            {
            last:
                tmp.words[15] = ENDIAN_n2b32( bitlen );
                sha256_do( state, tmp.bytes );
                int i;
                for( i = 0; i < 8; i++ )
                {
                    hash[i] = ENDIAN_n2b32( state[i] );
                }
                break;
            }
            else
            {
                sha256_do( state, tmp.bytes );
                memset( tmp.words, 0, sizeof( tmp ) );
                goto last;
            }
        }
        else
        {
            sha256_do( state, msg );
            msg += 64;
            len -= 64;
        }
    }
}

uint32_t crc( const uint8_t* buf, int len )
{
    uint32_t crc = 0xFFFFFFFF;
    while( len-- > 0 )
    {
        crc = crc ^ *buf++;
        for( int i = 0; i < 8; i++ )
        {
            uint32_t mask = -( crc & 1 );
            crc           = ( crc >> 1 ) ^ ( 0xEDB88320 & mask );
        }
    }
    return ~crc;
}
uint32_t compute_crc_fw( void )
{
#if defined( LR1110_MODEM )
    uint32_t crctmp =
        crc( ( uint8_t* ) ( START_FLASH_ADRESS ),
             ( *( uint32_t* ) FLASH_PROG_LEN ) * 4 );  // prog length in word is store in start_fw_flash_address
    return crctmp;
#else
#warning "compute_crc_fw NOT YET IMPLEMENTED"
    return 0;
#endif  // LR1110_MODEM
}